drivers/clk/at91/clk-generated.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (C) 2015 Atmel Corporation,
   4  *                     Nicolas Ferre <nicolas.ferre@atmel.com>
   5  *
   6  * Based on clk-programmable & clk-peripheral drivers by Boris BREZILLON.
   7  */
   8
   9 #include <linux/bitfield.h>
  10 #include <linux/clk-provider.h>
  11 #include <linux/clkdev.h>
  12 #include <linux/clk/at91_pmc.h>
  13 #include <linux/of.h>
  14 #include <linux/mfd/syscon.h>
  15 #include <linux/regmap.h>
  16
  17 #include "pmc.h"
  18
  19 #define GENERATED_MAX_DIV       255
  20
  21 struct clk_generated {
  22         struct clk_hw hw;
  23         struct regmap *regmap;
  24         struct clk_range range;
  25         spinlock_t *lock;
  26         u32 *mux_table;
  27         u32 id;
  28         u32 gckdiv;
  29         const struct clk_pcr_layout *layout;
  30         struct at91_clk_pms pms;
  31         u8 parent_id;
  32         int chg_pid;
  33 };
  34
  35 #define to_clk_generated(hw) \
  36         container_of(hw, struct clk_generated, hw)
  37
  38 static int clk_generated_set(struct clk_generated *gck, int status)
  39 {
  40         unsigned long flags;
  41         unsigned int enable = status ? AT91_PMC_PCR_GCKEN : 0;
  42
  43         spin_lock_irqsave(gck->lock, flags);
  44         regmap_write(gck->regmap, gck->layout->offset,
  45                      (gck->id & gck->layout->pid_mask));
  46         regmap_update_bits(gck->regmap, gck->layout->offset,
  47                            AT91_PMC_PCR_GCKDIV_MASK | gck->layout->gckcss_mask |
  48                            gck->layout->cmd | enable,
  49                            field_prep(gck->layout->gckcss_mask, gck->parent_id) |
  50                            gck->layout->cmd |
  51                            FIELD_PREP(AT91_PMC_PCR_GCKDIV_MASK, gck->gckdiv) |
  52                            enable);
  53         spin_unlock_irqrestore(gck->lock, flags);
  54
  55         return 0;
  56 }
  57
  58 static int clk_generated_enable(struct clk_hw *hw)
  59 {
  60         struct clk_generated *gck = to_clk_generated(hw);
  61
  62         pr_debug("GCLK: %s, gckdiv = %d, parent id = %d\n",
  63                  __func__, gck->gckdiv, gck->parent_id);
  64
  65         clk_generated_set(gck, 1);
  66
  67         return 0;
  68 }
  69
  70 static void clk_generated_disable(struct clk_hw *hw)
  71 {
  72         struct clk_generated *gck = to_clk_generated(hw);
  73         unsigned long flags;
  74
  75         spin_lock_irqsave(gck->lock, flags);
  76         regmap_write(gck->regmap, gck->layout->offset,
  77                      (gck->id & gck->layout->pid_mask));
  78         regmap_update_bits(gck->regmap, gck->layout->offset,
  79                            gck->layout->cmd | AT91_PMC_PCR_GCKEN,
  80                            gck->layout->cmd);
  81         spin_unlock_irqrestore(gck->lock, flags);
  82 }
  83
  84 static int clk_generated_is_enabled(struct clk_hw *hw)
  85 {
  86         struct clk_generated *gck = to_clk_generated(hw);
  87         unsigned long flags;
  88         unsigned int status;
  89
  90         spin_lock_irqsave(gck->lock, flags);
  91         regmap_write(gck->regmap, gck->layout->offset,
  92                      (gck->id & gck->layout->pid_mask));
  93         regmap_read(gck->regmap, gck->layout->offset, &status);
  94         spin_unlock_irqrestore(gck->lock, flags);
  95
  96         return !!(status & AT91_PMC_PCR_GCKEN);
  97 }
  98
  99 static unsigned long
 100 clk_generated_recalc_rate(struct clk_hw *hw,
 101                           unsigned long parent_rate)
 102 {
 103         struct clk_generated *gck = to_clk_generated(hw);
 104
 105         return DIV_ROUND_CLOSEST(parent_rate, gck->gckdiv + 1);
 106 }
 107
 108 static void clk_generated_best_diff(struct clk_rate_request *req,
 109                                     struct clk_hw *parent,
 110                                     unsigned long parent_rate, u32 div,
 111                                     int *best_diff, long *best_rate)
 112 {
 113         unsigned long tmp_rate;
 114         int tmp_diff;
 115
 116         if (!div)
 117                 tmp_rate = parent_rate;
 118         else
 119                 tmp_rate = parent_rate / div;
 120
 121         if (tmp_rate < req->min_rate || tmp_rate > req->max_rate)
 122                 return;
 123
 124         tmp_diff = abs(req->rate - tmp_rate);
 125
 126         if (*best_diff < 0 || *best_diff >= tmp_diff) {
 127                 *best_rate = tmp_rate;
 128                 *best_diff = tmp_diff;
 129                 req->best_parent_rate = parent_rate;
 130                 req->best_parent_hw = parent;
 131         }
 132 }
 133
 134 static int clk_generated_determine_rate(struct clk_hw *hw,
 135                                         struct clk_rate_request *req)
 136 {
 137         struct clk_generated *gck = to_clk_generated(hw);
 138         struct clk_hw *parent = NULL;
 139         struct clk_rate_request req_parent = *req;
 140         long best_rate = -EINVAL;
 141         unsigned long min_rate, parent_rate;
 142         int best_diff = -1;
 143         int i;
 144         u32 div;
 145
 146         /* do not look for a rate that is outside of our range */
 147         if (gck->range.max && req->rate > gck->range.max)
 148                 req->rate = gck->range.max;
 149         if (gck->range.min && req->rate < gck->range.min)
 150                 req->rate = gck->range.min;
 151
 152         for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
 153                 if (gck->chg_pid == i)
 154                         continue;
 155
 156                 parent = clk_hw_get_parent_by_index(hw, i);
 157                 if (!parent)
 158                         continue;
 159
 160                 parent_rate = clk_hw_get_rate(parent);
 161                 min_rate = DIV_ROUND_CLOSEST(parent_rate, GENERATED_MAX_DIV + 1);
 162                 if (!parent_rate ||
 163                     (gck->range.max && min_rate > gck->range.max))
 164                         continue;
 165
 166                 div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
 167                 if (div > GENERATED_MAX_DIV + 1)
 168                         div = GENERATED_MAX_DIV + 1;
 169
 170                 clk_generated_best_diff(req, parent, parent_rate, div,
 171                                         &best_diff, &best_rate);
 172
 173                 if (!best_diff)
 174                         break;
 175         }
 176
 177         /*
 178          * The audio_pll rate can be modified, unlike the five others clocks
 179          * that should never be altered.
 180          * The audio_pll can technically be used by multiple consumers. However,
 181          * with the rate locking, the first consumer to enable to clock will be
 182          * the one definitely setting the rate of the clock.
 183          * Since audio IPs are most likely to request the same rate, we enforce
 184          * that the only clks able to modify gck rate are those of audio IPs.
 185          */
 186
 187         if (gck->chg_pid < 0)
 188                 goto end;
 189
 190         parent = clk_hw_get_parent_by_index(hw, gck->chg_pid);
 191         if (!parent)
 192                 goto end;
 193
 194         for (div = 1; div < GENERATED_MAX_DIV + 2; div++) {
 195                 req_parent.rate = req->rate * div;
 196                 if (__clk_determine_rate(parent, &req_parent))
 197                         continue;
 198                 clk_generated_best_diff(req, parent, req_parent.rate, div,
 199                                         &best_diff, &best_rate);
 200
 201                 if (!best_diff)
 202                         break;
 203         }
 204
 205 end:
 206         pr_debug("GCLK: %s, best_rate = %ld, parent clk: %s @ %ld\n",
 207                  __func__, best_rate,
 208                  __clk_get_name((req->best_parent_hw)->clk),
 209                  req->best_parent_rate);
 210
 211         if (best_rate < 0 || (gck->range.max && best_rate > gck->range.max))
 212                 return -EINVAL;
 213
 214         req->rate = best_rate;
 215         return 0;
 216 }
 217
 218 /* No modification of hardware as we have the flag CLK_SET_PARENT_GATE set */
 219 static int clk_generated_set_parent(struct clk_hw *hw, u8 index)
 220 {
 221         struct clk_generated *gck = to_clk_generated(hw);
 222
 223         if (index >= clk_hw_get_num_parents(hw))
 224                 return -EINVAL;
 225
 226         if (gck->mux_table)
 227                 gck->parent_id = clk_mux_index_to_val(gck->mux_table, 0, index);
 228         else
 229                 gck->parent_id = index;
 230
 231         return 0;
 232 }
 233
 234 static u8 clk_generated_get_parent(struct clk_hw *hw)
 235 {
 236         struct clk_generated *gck = to_clk_generated(hw);
 237
 238         return gck->parent_id;
 239 }
 240
 241 /* No modification of hardware as we have the flag CLK_SET_RATE_GATE set */
 242 static int clk_generated_set_rate(struct clk_hw *hw,
 243                                   unsigned long rate,
 244                                   unsigned long parent_rate)
 245 {
 246         struct clk_generated *gck = to_clk_generated(hw);
 247         u32 div;
 248
 249         if (!rate)
 250                 return -EINVAL;
 251
 252         if (gck->range.max && rate > gck->range.max)
 253                 return -EINVAL;
 254
 255         div = DIV_ROUND_CLOSEST(parent_rate, rate);
 256         if (div > GENERATED_MAX_DIV + 1 || !div)
 257                 return -EINVAL;
 258
 259         gck->gckdiv = div - 1;
 260         return 0;
 261 }
 262
 263 static int clk_generated_save_context(struct clk_hw *hw)
 264 {
 265         struct clk_generated *gck = to_clk_generated(hw);
 266
 267         gck->pms.status = clk_generated_is_enabled(&gck->hw);
 268
 269         return 0;
 270 }
 271
 272 static void clk_generated_restore_context(struct clk_hw *hw)
 273 {
 274         struct clk_generated *gck = to_clk_generated(hw);
 275
 276         if (gck->pms.status)
 277                 clk_generated_set(gck, gck->pms.status);
 278 }
 279
 280 static const struct clk_ops generated_ops = {
 281         .enable = clk_generated_enable,
 282         .disable = clk_generated_disable,
 283         .is_enabled = clk_generated_is_enabled,
 284         .recalc_rate = clk_generated_recalc_rate,
 285         .determine_rate = clk_generated_determine_rate,
 286         .get_parent = clk_generated_get_parent,
 287         .set_parent = clk_generated_set_parent,
 288         .set_rate = clk_generated_set_rate,
 289         .save_context = clk_generated_save_context,
 290         .restore_context = clk_generated_restore_context,
 291 };
 292
 293 /**
 294  * clk_generated_startup - Initialize a given clock to its default parent and
 295  * divisor parameter.
 296  *
 297  * @gck:        Generated clock to set the startup parameters for.
 298  *
 299  * Take parameters from the hardware and update local clock configuration
 300  * accordingly.
 301  */
 302 static void clk_generated_startup(struct clk_generated *gck)
 303 {
 304         u32 tmp;
 305         unsigned long flags;
 306
 307         spin_lock_irqsave(gck->lock, flags);
 308         regmap_write(gck->regmap, gck->layout->offset,
 309                      (gck->id & gck->layout->pid_mask));
 310         regmap_read(gck->regmap, gck->layout->offset, &tmp);
 311         spin_unlock_irqrestore(gck->lock, flags);
 312
 313         gck->parent_id = field_get(gck->layout->gckcss_mask, tmp);
 314         gck->gckdiv = FIELD_GET(AT91_PMC_PCR_GCKDIV_MASK, tmp);
 315 }
 316
 317 struct clk_hw * __init
 318 at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock,
 319                             const struct clk_pcr_layout *layout,
 320                             const char *name, const char **parent_names,
 321                             u32 *mux_table, u8 num_parents, u8 id,
 322                             const struct clk_range *range,
 323                             int chg_pid)
 324 {
 325         struct clk_generated *gck;
 326         struct clk_init_data init;
 327         struct clk_hw *hw;
 328         int ret;
 329
 330         gck = kzalloc(sizeof(*gck), GFP_KERNEL);
 331         if (!gck)
 332                 return ERR_PTR(-ENOMEM);
 333
 334         init.name = name;
 335         init.ops = &generated_ops;
 336         init.parent_names = parent_names;
 337         init.num_parents = num_parents;
 338         init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
 339         if (chg_pid >= 0)
 340                 init.flags |= CLK_SET_RATE_PARENT;
 341
 342         gck->id = id;
 343         gck->hw.init = &init;
 344         gck->regmap = regmap;
 345         gck->lock = lock;
 346         gck->range = *range;
 347         gck->chg_pid = chg_pid;
 348         gck->layout = layout;
 349         gck->mux_table = mux_table;
 350
 351         clk_generated_startup(gck);
 352         hw = &gck->hw;
 353         ret = clk_hw_register(NULL, &gck->hw);
 354         if (ret) {
 355                 kfree(gck);
 356                 hw = ERR_PTR(ret);
 357         }
 358
 359         return hw;
 360 }